The Role of Gases in Groundwater Contamination and Remediation

地下水是一种重要的自然资源。大约有1000万加拿大人依靠地下水作为饮用水来源。它也是地表水和更深层次的区域系统之间的重要纽带，也是加拿大工业的水源，包括农业和石油和天然气。我们的地下水质量受到污染的威胁。加拿大有数以万计的受污染地点，其中许多是位于市中心和海滨的棕地物业。清理这些网站的成本是巨大的，可能总计数百亿美元。地下水中的气体在地下水污染中扮演着重要但往往被忽视的角色。例如，气体可以是自然产生的，也可以通过修复技术产生，它们会影响地下水的流动(通过降低渗透率)以及污染物的传输和反应(通过气体和地下水之间的传质)。气体本身也可能是污染物。例如，页岩气开采的迅速增加导致人们更加关注环境影响，包括甲烷气体对饮用水含水层的污染。

Groundwater is a vital natural resource. Approximately 10 million Canadians rely on groundwater as a source of drinking water. It is also an important link between surface water and deeper regional systems, and is a source of water for Canadian industries, including agriculture and oil and gas. The quality of our groundwater is threatened by contamination. There are tens of thousands of contaminated sites in Canada, many of which are brownfield properties located in urban centres and along waterfronts. The cost to clean up these sites is substantial, and likely totals tens of billions of dollars. Gases in the subsurface play an important, but often underappreciated, role in groundwater contamination. For example, gases can be created naturally or by remediation technologies, and they affect the flow of groundwater (by reducing permeability) as well as the transport and reaction of contaminants (by mass transfer between the gas and groundwater). Gases can also be contaminants themselves. For example, the rapid increase in shale gas extraction has led to increased concern over environmental impacts, including the contamination of drinking water aquifers by methane gas.